The invention relates to the general field of cutting pieces out from swatches (or remnants) of flexible material, in particular swatches of thick material having edges in which undulations and then folds are likely to form.
A field of application of the invention is that of cutting natural leather or hide, in particular in the furnishing, saddlery, upholstery, in particular car upholstery, leather goods, luggage, shoe, and clothing industries.
In manner known per se, the process of cutting pieces out from a swatch of flexible material, such as a hide for example, is performed as follows: The hide to be cut is firstly prepared, i.e. an operator marks possible defects in the hide and identifies them directly thereon by means of marks. The hide with its marks is then scanned. From the digital representation of the hide and by means of appropriate software, the operator puts the various pieces that must be cut out from the hide into place in optimum manner. The placement is converted into a cutting program for cutting the pieces. The hide is then positioned on the cutting table for cutting by means of a cutter tool that moves through the hide in accordance with the pre-established cutting program for cutting out the pieces.
When the hide is positioned on the cutting table, it is generally held there, flattened by a suction system arranged below the table. However, despite the suction, undulations can exist, in particular at the edges of the hide. The presence of such undulations is explained in particular by the fact that it is difficult to spread a hide, which is originally a three-dimensional (3D) piece, out flat on a plane.
As the cutter tool passes, the undulations move and may accumulate, creating folds in the hide. When the undulations in the hide do not transform into folds, there is the risk of obtaining a cut piece that is not properly shaped because it has been deformed. Furthermore, when the undulations accumulate so as to form edge folds, there exists a risk that such folds slow down or even interrupt the operation of cutting the hide. Specifically, when the cutter tool encounters an edge fold, this generates an error that requires the cutter tool to be raised and moved away so as to enable the hide to be put correctly into place manually, the fold to be flattened, and then the cutting program to be re-started.
Such manipulations for correcting the error generated by the presence of an edge fold in the hide considerably slow down the operation of cutting the hide. When errors are repeated several times on a single hide, the productivity of the cutting process is greatly affected. Furthermore, even when they do not transform into edge folds, undulations affect the quality of the cuts made in the hide.
A need thus exists for a method that makes it possible to guarantee flattening (or smoothing) of the hide prior to cutting it.
Document FR 2 518 575 discloses a method of smoothing a hide, which method consists in controlling a treatment cylinder that exerts a smoothing and pressing action on the hide, the treatment cylinder performing several passes so as to treat all of the surface area of the hide at least once. Such a method presents numerous drawbacks. In particular, it requires the use of a special tool for smoothing the hide (namely the treatment cylinder). Furthermore, it is relatively lengthy since the entire surface area of the hide is subjected to the smoothing treatment. Finally, it does not present a smoothing strategy adapted to the specific outline of each hide to be cut.